Detergent products employed in automated car washes usually include two broad types of chemical products inorganic alkalinity builders and organic surfactants. These detergents are typically delivered to car wash operators, ready to use, in concentrated liquid and powdered forms. Various difficulties, however, limit the concentration at which the detergents can be distributed and negatively influence the profit margin of capital-intensive, car washing businesses.
Because of well-known instability problems, liquid detergents must often be diluted with water and enhanced with costly stabilizing agents to prevent their breakdown during transit and subsequent storage prior to use. The disadvantages associated with increasing the fraction of water in a given detergent mixture are many, and associated manufacturing, packaging, transporting, and handling costs normally rise in proportion to the amount of water contained therein. Of course, highly concentrated liquid surfactants, absent the usual inorganic compounds, can be procured, but such are generally considered to be less effective as cleaning agents.
Detergents, delivered in powdered form, typically include a mix of finely divided phosphates, silicates and carbonates as well as a modest amount of evenly distributed liquid surfactant. Generally, the surfactant concentration in the resulting detergent composition is limited to approximately 15 percent by weight. Excess amounts of the surfactant result in powders wherein the individual granules tend to adhere to one another and fail to flow through state-of-the-art blending and dispensing equipment.
Dispensing premixed, powdered detergents in a modern car wash is especially problematic. Hand measurement of the detergent by inexperienced workmen is time consuming and prone to mistake. Detergent over-concentration can result in waste if separation of the several detergent components in the solution holding tank results. Automatic dispensing equipment, on the other hand, frequently yields detergents which lack effective concentrations of intended constituents due to their relative variations in water solubilities. Further, prolonged and unchecked dampness can lead to consolidation of the powdered material so as to completely prevent admission of the detergent into the car wash fluid stream through automated means.